Fuzzy logic based sensorless adaptive direct torque control of surface permanent magnet synchronous motor (SPMSM) drives

In this paper, a fuzzy logic based direct torque control method for permanent magnet synchronous motor has been proposed. Conventional direct torque control method may suffer from much torque ripple during command transients. The fuzzy logic based system proposed hereby is more accurate and can adapt quickly to varying conditions such as speed reversal, step change in torque or speed etc. In this research, a fuzzy inference system has been designed to make a human machine interface and the dynamic and steady state response error has been reduced to a much smaller value. Apart from this, the control system is made to cope with varying condition of loads during transients. The robustness to parametric uncertainty is substantiated by varying inertia, inductance, dc link voltage etc for a viscous load. A comparative study between conventional and fuzzy based direct torque control has been carried out for constant load to investigate the effectiveness of the proposed method. The system performance has been tested via computer simulation.